How Does Trent Send a Cipher Message to Bob, Alice and Carol, And Not Know What Reads the Message?
How Does Trent Send a Cipher Message to Bob, Alice and Carol, And Not Know What Reads the Message?
Let’s say that the Trent wants to send Bob, Alice and Carol a secret message, but where Trent cannot determine who will actually read the message. In this case we will generate key pairs for Bob, Alice and Carol, and Trent will encrypt a message for them. We will then use one of the private keys to decrypt the encrypted message with the private key of either Bob, Alice or Carol.
Trent thus creates an encryption key from the public keys, and sends the cipher. Next Bob, Alice or Carol can take the public keys in a set, and then use their own private key to decrypt the message. Trent will have no idea who has actually read the message or which private key has been used. Here is the code [here]:
A sample run is [here]:
Encryption of 'qwerty':
00000000 1f ef 1c cb a6 1a d4 83 fd 8f 59 fb 8b 15 0b ff |..........Y.....|
00000010 4d a4 df f8 31 ee 3c b8 7b 03 f5 ee ee 56 62 d4 |M...1.<.{....Vb.|
00000020 6a fa c1 43 16 69 97 dd 77 c0 28 f1 17 05 a5 08 |j..C.i..w.(.....|
00000030 2e 0c a1 b7 b5 39 ee 6a 2d 45 8e 14 e7 8a 07 f2 |.....9.j-E......|
00000040 fc a4 22 d0 f5 51 36 c2 a0 3a 26 74 5b c5 19 f3 |.."..Q6..:&t[...|
00000050 22 fc 7c 27 a6 80 7a ea cb 4a 11 d6 a8 ed 3b 6c |".|'..z..J....;l|
00000060 54 f1 22 c8 2a e3 28 8b 0b 20 62 c7 4e de 72 a5 |T.".*.(.. b.N.r.|
00000070 e2 a8 e9 94 fd 68 cf 3f e4 88 b7 1a 1d ec a0 c6 |.....h.?........|
00000080 ca d7 7c 90 c1 30 f7 70 7e 87 08 91 2c 25 9c 68 |..|..0.p~...,%.h|
00000090 2b bd 81 8e fc 8b |+.....|
Bob key: '97bb9cebdd5e07e94d2980bb920b83e16cf4f6ed078f50cca8ba19cdd887ea0c'
Alice key: '1ef8829b3ab57cd409999d8f8ef2d282fea13e14c5c25e82ba25392372d07005'
Carol key: '3b33b8b240724ac33aa4b499a3550e9a3d644cdd565def1ecda19cee3867a702'
Decrypted (Bob) : 'qwerty'
Decrypted (Alice): ''
Decrypted (Carol): ''
We live in a world which releases so much information. In this case we can gather a number of public keys, some of which may be dummy keys, and where Trent will not be able to determine which of the public keys are actually valid and which on has the associated private key which will read the message.